This disclosure relates in general to filling containers with powder, and more particularly, to fill to a very complete level, different shaped containers.
Typically, a hopper for flowable bulk materials, such as, dry powders or toner used in copiers/printers has a vertical cylindrical section joined at its lower edge to a conical or frusta-conical section. A funnel is joined at the lower edge of the conical or frusta-conical section of the hopper. The hopper is filled through an inlet opening at the top of the cylindrical section, and is emptied through an outlet at the lowermost point of the funnel into a container.
It is common when filling powders, for example, toners into toner containers, for the toner to be transported from a funnel portion of a toner supply hopper, through a funnel into the containers by a rotating auger. The auger is a spiral shaped mechanical part that pushes particles of toner through the hopper by direct mechanical contact. The nature of this mechanical contact process creates substantial limitations on accuracy and productivity of the toner filling operation. The problem presented is to dispense toner that will flow to all areas of the containers thereby packing the greatest mass of toner into the containers. Unfortunately, dispensing dense toner continuously does not sufficiently fill voids in the containers because dense toner does not flow well. Also, dense toner occasionally causes a startup condition that results in the auger “seizing” in the discharge or funnel area of the hopper and funnel. In order to restore the operation of the filler in this case, the hopper and funnel must be partially disassembled and the packed toner removed. This causes significant material and productivity loss. Continuously dispensing less dense toner prevents the required mass of toner from being added before the toner overfills the container. A resolution is to adjust process parameters to find a compromise density that will minimize “seizes” and still fill the containers to the required level. However, this single density choice does not maximize the mass of toner that can fill a container.
Problems with filling toner in small containers that fit into tight spaces are exacerbated in that toner containers for small, low cost printers and copiers are produced in higher quantities necessitating very efficient toner filling operations. In addition, toner containers for small, low cost printers and copiers typically have irregular shapes to conform to the allotted space within the printer or copier. Therefore, it becomes difficult to fill the toner container because of the small funnel required to fit into the toner container opening and secondly for all of the toner within the container to completely fill the remote portions of the container before the container overflows.
One attempt at improving the flow of powders includes U.S. Pat. No. 5,921,295 issued Jul. 13, 1999 to Joseph S. Zelazny et al. that employs a high-speed nozzle for toner filling systems. The apparatus includes a conduit that is connected to and extends downward from a hopper and is adapted to permit a flow of power therethrough with the help of an auger. A nozzle is connected to the conduit and receives powder from the conduit and passes it into a container. The dimensions of the nozzle are selected so as to provide a ratio of the inlet cross sectional area to the outlet cross sectional area such that the flow of powder does not seize as it progresses through the nozzle.
Obviously, there is still a need for an apparatus that will dispense toner from a nozzle that will flow to all areas of a container thereby packing the greatest mass of toner into the container.
Accordingly, an improved method and apparatus is disclosed for filling containers of different shapes with powder that includes an apparatus for controlling the denseness of powder conveyed from a hopper through a funnel and into a container and includes an auger that is positioned within the hopper and funnel and adapted to rotate and move vertically. The rotation and vertical movement of the auger serves to continuously vary the length of the auger and as a result maximizes the mass of powder that can fill the container. Alternatively, the auger can include an articulatable section that splays when it is extended beyond a terminal portion of the funnel to thereby control the denseness of powder during a filling operation. As another alternative, the apparatus could include a hollow auger shaft with a rod positioned therein that is adapted to extend and retract with respect to the funnel. The rod includes a strip portion and with the strip portion retracted within the funnel, the powder discharged is in the densest state. As the strip portion is extended beyond an end portion of the funnel the powder density is reduced.
While the disclosure will be described hereinafter in connection with a preferred embodiment thereof, it will be understood that limiting the disclosure to that embodiment is not intended. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.